The Northeast Heatwave

By: Dr. Jeff Masters , 09:08 GMT le 07 juillet 2010

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Hi, Dr. Rob Carver, filling in for Jeff while he's on vacation.

The most significant weather event in the US on July 6, 2010 didn't show up on any radar. The geostationary satellites didn't see it in their constant watch over the Earth's atmosphere. Instead, the tale of this event was told by the thermometers, because the heatwave in the Northeast was the most significant event for July 6, and it will likely be the most important weather story for July 7.

The heat wave covers Pennsylvania to Maine, but Tuesday's worst was centered over New York City. All six of the stations used by the New York NWS office for climate reports (Central Park, La Guardia, JFK, Islip, Bridgeport, and Newark) set or tied the daily high temperature record. Newark and Central Park both reached 103 degrees F.

How unusual is this heat wave?
Figures 1 and 2 show how warm the highs and lows are compared to 30 year averages. Unless you were at the Great Lakes, the Midwest and Northeast have highs well above normal, with 10-15+ degree F differences over the coastal cities of the Northeast. Using my gridded temperature data, the low for New York City was 6 degrees F above normal, which should happen 30% of the time (1.1 standard deviations away from normal). The high was roughly 20 degrees above normal, which should happen only 0.29% of the time (3.04 standard deviations away from normal). This is an unusually strong heat wave.

Why it's hot
Basically, it's because there is "the Bull of a high pressure ridge [over the NE US]" to quote the Mount Holly NWS office forecast discussion. The large ridge of high pressure is forcing air to slowly descend across the Northeast, preventing clouds from forming. Without no clouds and plenty of daylight, the Sun heats the ground which then heats the air.

When will it cool down?
That's an excellent question. A trough of low pressure off the coast will bring onshore winds to the Tri-State area and MA by Thursday, so they should cool down a bit. The southern part of the heat wave, DC and Philadelphia, will have to wait for a cold front to arrive from the Great Lakes sometime Saturday to get relief.

Population affected
As Figure 3 shows, heat advisories covered most of the urban areas of the northeastern US. By my calculations, over 32 million people were under a heat advisory. Different offices have different guidelines for heat advisories. The NWS office responsible for New York issues a heat advisory if the heat index will be above 95 deg. F for two or more days or if the index will be above 100 deg. F for any length of time.


Fig.1 Plot of the difference between maximum temperature (the high for the day) and average maximum temperature in degrees F for July 6.


Fig.2 Plot of the difference between minimum temperature (the low for the day) and average minimum temperature in degrees F for July 6.


Fig.3 Plot of the active heat advisories across the northeastern US for July 6.

Heatwave impacts
The predominant impact from heat waves is increased mortality. CDC estimates that over 8,000 people died during heat waves from 1979 to 2003. That's more than all of the deaths due to lightning, flooding, tornadoes, hurricanes, and earthquakes. The elderly, sick, poor, and very young face the worst of the effects of the heat. Wikipedia has an interesting article describing the Chicago Heat Wave of 1995, a modern heat wave with a large number of fatalities due to the heat.

Heatwave coping strategies
The Centers for Disease Control have some tips for dealing with the heat. In summary, drink plenty of water, spend time in air-conditioned buildings, and wear light-colored clothing.

Is this heat wave due to global warming?
Ah, the $64,000 question. In the absence of detailed analysis, it's hard to specify the exact cause for this heat wave, from a meteorological or climatological view point. However, events like this are consistent with research showing that heat waves are more likely with
global warming
. I like the metaphor of loaded dice, global warming is not specifically responsible for any heat wave, but it will make them happen more often.

Tropics
My thinking on Invest 96L is unchanged from this blog entry. In summary, I believe that 96L has a <50 % chance becoming a tropical cyclone before it makes landfall. If it does so, it will likely be near the coast when that happens. In any event though, the winds and waves it generates will likely disrupt oil spill recovery efforts. Also, I would expect a broad area of showers and 20+ mph winds will affect the Gulf coast somewhere from south Texas to Louisiana.

Next update
I'll have an update this afternoon to talk about the tropics.

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POLO!!!
Member Since: 24 janvier 2007 Posts: 317 Comments: 31946
384. Daveg
LOL... I think all the deadcasters are going to be sadly mistaken.

No, I really don't think it will become a hurricane, but 96L is far from dead.
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Gotta do it....

MARCO!!!!!
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I give 96L a 10% chance for development before it makes landfall somewhere in Texas. However, the NHC might want to take more notice to the NON-TROPICAL low near Bermuda, could gain some Subtropical characteristics since it's sitting there in the warm waters. I give this a 30% for SUBtropical development. The waves coming off Africa continued to get sheared as they past 40W. I don't expect shear to decrease until after 200 hours or so as the EURO suggests something may try to get going by 240 hours.
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Quoting DestinJeff:
RIP 96L
Quoting DestinJeff:
RIP 96L


that's just what I was thinking.
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RIP tropics for next couple weeks.
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Tick ,Tock,Tick,Tock.
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Zzzzzzzzzzzzzzz
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I see.
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sorry, I was trying to quote post #362. The blog's like early '05, not the season (at least I hope not. :-/
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Quoting watchingnva:


true...but 92-98 with dewpoints of 73+ is really gonna feel that much better? lol...

and i know we have a chance of rain through the weekend...but wanna bet we dont get a drop right around here...itll rain west, north and east...but fall apart if it heads this way...lol...thats what it has been doing the last 2 months...is our luck gonna change?...lol


ROFL - Same here in Central VaBeach - the storms roll over the airport (west of me) and up Great Neck Rd (east of me). I can see the clouds - even the rain trails, and get not a single drop.
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Link Two interesting features are approaching the Lesser Antilles. Visible sat. shows decent cyclonic turning with both waves and this also shows on the most recent vorticity maps. Convection seems to be increasing with both, although drier air in the vacinity may keep heavy thunderstorms under check for a while. These will have to be watched over the next few days....
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I see 96L has grown less organize as it failed to take advantage of the diurnal maximum this morning. The storm ended up doing what the ECMWF forecasted which was for the mid level center to decouple to the north and leave the surface center trailing WNW. A buoy south of the system is reporting winds out of the ENE at this time suggesting that 96L does not have a closed circulation. In addition, visible satellite loops show outflow boundaries denoting collapsing thunderstorms llikely due to dry air west of the system.
Member Since: 28 octobre 2006 Posts: 57 Comments: 30825
2005 had 4 named storms by now.
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It's kind of like early '05...check out Dr. M's blog archives from early that season. There were posts with 2 and 6 and 21 comments.
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Quoting tropicfreak:


Morning watch!! Today will be our last day in the triple digits! Wohoo!!


true...but 92-98 with dewpoints of 73+ is really gonna feel that much better? lol...

and i know we have a chance of rain through the weekend...but wanna bet we dont get a drop right around here...itll rain west, north and east...but fall apart if it heads this way...lol...thats what it has been doing the last 2 months...is our luck gonna change?...lol
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Is this the home shopping blog?lol!
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366. Daveg
Quoting LoneStarWeather:
Wow, this blog is "deader" than 96L!


Not anywhere near dead.
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Quoting LoneStarWeather:

We had an awesome storm in Richmond, TX yesterday evening about 7. Lots of lightning and thunder and a flood advisory. It just doesn't get any better than that!


We caught the edge of that storm in Katy.

I grew up outside of Dallas. People down here just don't really know what a thunderstorm is. ;)
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Quoting HurricaneSwirl:


Lol I don't understand it either. But you better be used to it today as this is gonna be the worst of it for you guys. Then it's our turn come thursday :(, although we're still only forecast to hit 101-102, which is still a nice couple of degrees cooler than what you're getting today so im fine :)

Man and on the topic of scorching boulders I remember going to Jekyll island last year during a heat wave that brought heat indexes up to around 120 degrees.. I literally burnt my feet on the sand, and I thought the water would cool me down. It didn't :(


yea....i really wish we could get a couple fronts coming through like we had last wed/thurs...dropped it into the mid 80s with dewpoints in the 50's...it was nice...too bad it couldnt last...knowing how things have been so far this summer...its gonna be in the mid 90's with higher humidity through early next week...then we will go 3-4 days back above 100...seems like the trend weve had the last month or so...
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whiskey tango foxtrot?
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Wow, this blog is "deader" than 96L!
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Quoting atmoaggie:
Want to never be overly hot again?

Had a job one summer at Texas A&M tending to cotton fields. All work by hand, no machines. Weeks of ~100 F and just under 70F dewpoints and out in it 10 hours a day.

Try it and no amount of hot will actually bother you ever again...


I may have you beat: I worked for a Miami-area roofing company as a hot mopper, which basically consisted of standing on a pitched or flat roof in the middle of the summer heat and humidity while slinging around buckets full of 650-degree bitumenous asphalt...all while wearing full-length protective coveralls. Yeah, that job was a real hoot... :-)
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Quoting angiest:


Erg, don't get me started. I am already seeing Christmas decorations in stores.


Oh hush. Here many kids in Richmond including myself just started summer 2-3 weeks ago, we will start school the day after labor day. At Target, they already have "Back to School Savings". We just started summer!!!!!!!!!!!!
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Quoting ElConando:
Wade and Bosh to Miami!!!!

Erm I mean hows 96L?
Isn't it amazing what a trip to south beach will do?
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We caught the last storm of the evening last night in Spring at about 10:30. Picked up a quick 1 inch and 1 clap of thunder before daytime heating lost out. I suspect we'll get a good deal more today and tomorrow...
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357. Daveg
Wow... 96L sure didn't move much over night. Still barely off land.

Trying to get her act together...
AVN Color Imagery Loop

I guess the day shall tell.
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Quoting watchingnva:


i dont understand how they can have severe air quality alerts and ozone alerts, and all this...but not put an advisory out...lol...maybe bc weve already had like 7-10 days of 100+ days here this summer that they think we are use to it:))...and my family and i were the smart ones who when to the beach on monday...and the river in downtown richmond yesterday...never again going to belle isle on a 100+ days...the boulders were scorching...you could fry an egg on them if you wanted to, and there are freaking river rocks with rapids around them...lol...too hot...dry heat i dont usually have a problem with...but 103-105 with a dewpoint higher than 65...no thank you...lol


I'm pretty surprised as well. No one in VA is under an advisory except for a few counties in N VA near DC.
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Quoting txalwaysprepared:
Loving the sound of thunder (we had lots of rain from Alex, but no thunder)

We had an awesome storm in Richmond, TX yesterday evening about 7. Lots of lightning and thunder and a flood advisory. It just doesn't get any better than that!
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Quoting help4u:
You know the tropics are dead when the talk is anything but tropics.Good day to go christmas shopping.lol


Erg, don't get me started. I am already seeing Christmas decorations in stores.
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Loving the sound of thunder (we had lots of rain from Alex, but no thunder)
Member Since: 18 août 2007 Posts: 0 Comments: 1642
thanks Dr C for keeping us uptodate
some of us are lurkers more than participants :)
btw - you should stick YOUR pic in when subbing for Dr M heheheh ;)
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You know the tropics are dead when the talk is anything but tropics.Good day to go christmas shopping.lol
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Quoting watchingnva:


im just se of richmond, and the dewpoint has been creeping up overnight and are now in the mid 60s to low 70's...70 here at the house...and the dewpoint in places like albany are only a few degrees higher at 73-76...so, im fairly confused as well...according to weather.gov....albany is only getting up to 96-98 with heat index of 103-105...while its gonna be 103-105 here today with an index of 106-108...lol...ive always wondered what the criteria has been...lol


Morning watch!! Today will be our last day in the triple digits! Wohoo!!
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Quoting HurricaneSwirl:
I have a question about what warrants heat advisories, they seem awful inconsistent to me..

Albany, NY will likely get to 95 today, but it is going to humid enough to put the heat index between 101 and 104. They are under a heat advisory.

Richmond, VA will likely get to 101-104 today, but it is dry enough so that the heat index probably won't surpass 106 or 107. They are not under a heat advisory.

Macon, GA will likely get to 95-98 today, but it is humid enough that the dew point will likely push heat indexes to around 105. They are not under a heat advisory.

When I saw Richmond wasn't under a heat advisory, yet it was going to be 10 degrees warmer than places that were, I thought it would be a humidity thing. But if it was a humidity thing then us in Macon would be under one too, so it can't be that... Man I'm confused.


You're right about Richmond, all the local forecasts in my area say at least 103! Heat indexs won't be a big factor because its not going to be humid.
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DestinJeff.....I love it!!!!!

:)
Member Since: 24 janvier 2007 Posts: 317 Comments: 31946
Quoting AussieStorm:
Well all, I am off to bed. But I will leave you with this....

Currently at Homebush, Sydney, Australia.
Temperature 47.1°F falling
Dew Point 39.9°F falling
Feels Like 47.1°F
Relative Humidity 76%
Wind
Wind Gusts -
Pressure -
Fire Danger -
Rain since 9am/last hr 0.0mm /

______________________________________________________________________________________________

Alice shivers through coldest day on record


Alice Springs has had its coldest day on record, shivering through single digit temperatures yesterday.

Sally Cutter from the weather bureau says Alice Springs reached a maximum of just 6.4 degrees celsius yesterday afternoon(43.5F).

"That makes it the coldest on record for Alice Springs and those records are fairly old," she said.

"I think it was 1948 was the coldest July day and 1966 was the previous coldest day on record."

The Northern Territory's previous coldest day was 5.9 degrees celsius(42.6F) , recorded in Yulara in 1997.

The wet conditions are continuing in Alice Springs, with the airport recording almost 70 millimetres(2.7inches) of rain since the start of the month.

The average rainfall for July in Alice Springs is 14 millimetres(0.5inches).

© ABC 2010


You are not winning any sympathy's here... I'd take 40's over 100's any day.
Member Since: 10 Mars 2006 Posts: 0 Comments: 10775
Wade and Bosh to Miami!!!!

Erm I mean hows 96L?
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Jim williams said at this time in 2005 we already had 4 named storms,with dry air and cooler tchp i would say 2005 is safe to keep it's record.
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cold and rainy here.....
Member Since: 24 janvier 2007 Posts: 317 Comments: 31946
then again, I've never had to shovel snow in a blizzard either....
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341. Inyo
yeah heat advisories are in theory based on how the heat affects people. True, it is often this hot in Florida and Death Valley and such. However, I live in Vermont and am currently in Pittsburgh - in both places a lot of people do not have AC at all and in Pittsburgh it is also really difficult to find a place to sleep outside. So it is pretty much miserable here... it would be hard to find anyone on the Gulf Coast without AC and anyone without it hopefully at least has an outdoor patio with a bug net to sleep on.

Kind of like flash flood warnings - 2 inches of rain in a few hours won't necessarily cause a flash flood in Georgia and no amount of rain can cause one in most of Florida since it is flat, but an inch of rain or less in a short period of time can cause flash flooding in the Southwest due to lack of vegetation, rock outcroppings, steepness, etc etc. Also a forecast of 1 inch of snow in January will trigger 'winter weather headlines' in Sacramento, California, because it is extremely rare to get snow there. If we had those warnings in Vermont every time we had 1 inch of snow they would be in effect for months and totally meaningless. It doesn't make sense to have nationwide standards for these things.
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Hey atmo...I did A/c work laying ducts in new home construction in central TX for a summer. That'll put hair on your chest, let me tell you. 100-102 outside everyday and I was in the attic.
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Quoting atmoaggie:
Want to never be overly hot again?

Had a job one summer at Texas A&M tending to cotton fields. All work by hand, no machines. Weeks of ~100 F and just under 70F dewpoints and out in it 10 hours a day.

Try it and no amount of hot will actually bother you ever again...


In blue jeans and a long sleeve button up shirt, right?

But of course, the clothes were probably cotton, not synthetic.
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Quoting Squid28:


I prefer a glass of milk and a Charleston Chew myself....

my hubby and I went to the movies with our 9 year old. matinee mind ya - $28 to sit and watch. Popcorn and drink extra. Geezum
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Want to never be overly hot again?

Had a job one summer at Texas A&M tending to cotton fields. All work by hand, no machines. Weeks of ~100 F and just under 70F dewpoints and out in it 10 hours a day.

Try it and no amount of hot will actually bother you ever again...
Member Since: Posts: Comments:

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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